FR2664308A1 - New-generation finished hard-packed (dirt) surface product - Google Patents

Abstract

Finished product for producing hard-packed sports surfaces (hard courts). The invention relates to a finished product ready for use which contains three different kinds of sand, mixed in a reconstituting station, at the ratio of 45% of eruptive (igneous) rock 0/2, 45% of metamorphic rock 0/1 and 10% of rolled silica 0/0.9, thus constituting a very-high performance covering (surface layer) for tennis courts. Its application is particularly suited to tennis courts for top-level competitions.

Description

 The present invention relates to a finished product for producing sports floors in clay. The finished product according to the invention is applicable mainly for the realization of tennis courts. However, its use can be extended to any sports field construction requiring a very important resistance to bad weather conditions, insensitivity to water and frost, an identical bounce of balls and stability for this non-evolutive layer for a period minimum of 5 years.

 The invention will now be described in the context of its application to tennis courts for high competitions.

The French Tennis Federation, driven by the desire to develop this sport on comfortable ground, intends to design a new generation of sports ground clay, passable at any time and at any time of the year.

Previously used land consisted, until 1980, of the superposition of a drainage network, a bed of calibrated pebbles and a screed. An improvement in the resistance over time of the screed has been successively provided by the presence of separating woven fabric, and subsequently a calibrated intermediate layer called base layer or layer of flexibility.

 The techniques concerning the structures of a tennis court are now perfectly defined up to the base layer, it is appropriate to focus more particularly on the screed that is the subject of the present invention.

 The screeds used up to now consist of natural products in the form of calcareous sands of particle size between 0 and 3 mm, perfectly freezing and very sensitive to water. They are characterized by a very important percentage of fines which evolves during the successive games, eventually creating dust and areas of hardness.

 Moreover, the excessive humidification of the courts, either manually or in bad weather, causes the creation of holes during the restart too early on the soaked surface. The terrain becomes ipso facto impractical due to false bounces and needs to be reworked.

The disadvantage of excessively friable limestone is slippage that can not be controlled and can be harmful to some competitive athletes.

 The evolution of the limestone screed requires, of course, several maintenance operations at the end of annual use. It is necessary to strip the surface layer, then to regenerate the soil in place by a soil conditioner or simply by alternative harrowing followed by dynamic compaction.

 The present invention overcomes all of these major disadvantages.

 The invention relates to a new type of screed consisting of three aggregates recomposed and forming a finished product ready for use.

 The aggregates used must be of a great regularity granulometric and of a great property making it possible to obtain a methodical and constant elaboration of the sought product.

 The first aggregate is an eruptive rock whose particle size is between 0 and 2 millimeters. It is 45% compounded, its resistance to frictional wear in the presence of water is less than 10 (MDE <10) and its LOS ANGELES impact strength is less than 2t (LA <20), its density is of the order of 2,600 Kg / m3.

The second granulate is a metamorphic rock perfectly recrystallized, whose particle size is between 0 and 1 millimeter, it comes in composition for 45%; his MICRO
DEVAL in the presence of water is less than 30 (MDE <30), its
LOS ANGELES less than 30 (LA <30), its density of the order of 1,900 Kg / m3.

The third granulate is a fully rolled siliceous sand whose particle size is between 0 and 900 microns. Its MICRO DEVAL in the presence of water is less than 25 (MDE <25), its LOS ANGELES less than 20 (LA <20), its density of the order of 2000 Kg / m3.

 The recomposition of the product is obtained in a mixing plant for the production of aggregates, or in a hydraulic concrete plant equipped with weight control feeders and a water flow meter.

The finished product is supplied ready to use, at its optimum water content. It will respond to a production curve included in the following time zone

<tb> Sieve <SEP> mm <SEP> 3 <SEP> 2 <SEP> 1 <SEP> 0.5 <SEP> 0.2 <SEP> 0.1 <SEP> 0.080 <SEP> 0.050 <SEP> 0 02
<tb><SEP> 100 <SEP> 100 <SEP> 90 <SEP> 75 <SEP> 56 <SEP> 38 <SEP> 34 <SEP> 28 <SEP> 20
<tb><SEP> to <SEP> 95 <SEP> to <SEP> 75 <SEP> a <SEP> 50 <SEP> to <SEP> 32 <SEP> to <SEP> 22 <SEP> to <SEP><SEP> to <SEP> 15 <SEP> a <SEP> 9
<Tb>
This production curve will lead to an acceptable compactness 6d
C =
SG with 6d = apparent dry density of finished product EG = actual density of aggregates
The optimal compactness will be obtained on a base layer consisting of a coke oven machefer washed and sorted at a thickness of 6 cm, compacted and set to plus or minus 0.5 cm and 7mm / m slope.

The invented product will be delivered at its optimum of water content of 10%, and then rolled by a non-vibrating roller of 700
Kg alternately.

 The watering frequency will be daily, it will be necessary to bring the water content to 15% the night before for the next day after passing the net. Any watering during the day should be avoided (see appendix 1 concerning the permeability and hydraulic retention test).

 The annual maintenance is obtained by scratching the superficial screed. The constituent elements of the screed do not vary from one year to another, so it is useless to deeply rework the product set up for a minimum period of 5 years.

 The interest of this invention is based on several parameters that were used to research the product.

1 The flexibility that is due to the general particle size of the product perfectly dosed and mixed brought to a compactness of the order of 68%.

 2 The insensitivity to water and frost due to the non-freezing product whose optimal water content varies from 5 to 15 t.

3 Compatibility with paint media where linseed oil is used as a support for white lines, which penetrates easily due to the lower percentage of fines thus forming a homogeneous binder for the part to be painted.

4 The draining power and permeability were tested in the laboratory as shown in Annex 1 of the single sectional figure or three (1) (2) (3) vessels with a diameter of 59 cm are superimposed. The first contains in A 21 cm of water is 57.41 liters that we dump in the second containing a tennis court structure, or B = 5 cm of compacted screed at a water content of 7%. In C = 6 cm compacted base coat, at 8% water content. In D = 12 cm pebbles 20/40 blocked. We find that water flows into the third tank after 1 minute at a rate of 1 liter per minute. The total quantity of water poured is received after 24 hours, ie 57.96 liters corresponding to a height of 21.2 cm in E. The product becomes perfectly draining after one minute and retains its optimum water content. 7% for 24 hours.

 The slipperiness is perfectly controlled by the presence of the rolled siliceous sand introduced at a rate of 10% into the mixture: Throughout the use, the slipperiness will remain the same, resulting from the lack of friability of the product.

6 The identical rebound at any point on the ground is ensured by the flatness obtained and the practical impossibility of creating ruts under the shear force due to successive starts. Indeed, the compactness obtained is greater than on the limestone and the rutting follows directly from the good granulometric curve and its implementation. The annual maintenance is improved to the extent that it is no longer necessary to "plow" the land and lose a lot of material.

The advantage of this new product particularly intended for the constitution of sports floor screeds, will in the near future to consider a revival of the practice of playing in all weather on clay and become the support of a study on how to humidify tennis courts without watering.

Claims (4)

1- Ready-to-use finished product with optimal water content characterized by the presence of three sands of different types, mixed in reconstitution plant, at 45% eruptive rock 0/2, 45% metamorphic rock 0 / 1 and 10% of silica rolled 0 / 0.9 and constituting the clevis of the tennis courts. 2- finished product according to claim 1, characterized in that the first of the aggregates is completely crushed particle size between 0 and 2 mm having a LOS ANGELES <20, a WET MICRO DEVAL <10 and a density of the order of 2,600 Kg / m3; in that the second of the aggregates is completely crushed with a particle size of between 0 and 1 mm having a LOS ANGELES <30, a WET MICRO DEVAL <30 and a density of the order of 1900 Kg / m3; in that the third granulate is a fully rolled siliceous sand with a particle size of between 0 and 900 microns of LOS ANGELES <25, of MDE <15, and a density of about 2000 Kg / m3. 3- finished product according to claim 1 and 2, characterized in that each granulate which composes it is non-gelling and non-evolutive in nature and grain size for a minimum period of five years. 4- Finished product according to claim 2, characterized in that its optimum water content is between 5 and 15% at the optimum proctor, compactness defined by the formula  Sd apparent dry density of finished product C = =  real density of the granules 5- Finished product according to claim 1, characterized in that its granulometric zone is defined by the following table

<tb> 6 finished product according to claim 2, characterized in that its friability is less than 15 (FS <15). <tb> <SEP> a <SEP> 95 <SEP> to <SEP> 75 <SEP> to <SEP> 50 <SEP> & <SEP> 32 <SEP> to <SEP> 22 <SEP> to <SEP> <SEP> to <SEP> 15 <SEP> to <SEP> 9 <SEP> <tb> <SEP> 100 <SEP> 100 <SEP> 90 <SEP> 75 <SEP> 56 <SEP> 38 <SEP> 34 <SEP> 28 <SEP> 20 <tb> Sieve <SEP> mm <SEP> 3 <SEP> 2 <SEP> 1 <SEP> 0.5 <SEP> 0.2 <SEP> 0.1 <SEP> 0.080 <SEP> 0.050 <SEP> 0 02  7 "Finished product according to claim 4, characterized in that the compaction is provided by a non-vibrating cylinder capable of ensuring the percentage of compactness equal to C. 8 finished product according to claim 1, characterized in that it is directly on the flexible layer as new generation clay.